Everything you need to know before purchasing a lawn trimmer

Lawnmowers are great for wide areas, but they can’t cut right up to fences and walls, or around tree trunks and other vertical objects.

For this uncut strip, you’ll need a line trimmer or brush cutter. They also make short work of overgrown weeds and straggly runners.

The difference between line trimmers and brush cutters is a bit of a grey area. A more helpful distinction is whether the tool uses a straight or bent shaft.

BENT-SHAFT models are typically the cheaper option, although slightly less torque is available at the hub.

STRAIGHT-SHAFT units are ideal for taller operators. They also offer extra reach to get under outdoor furniture and deeper into heavy scrub.

Cutting edge options

For heavy-duty applications such as thick, long grass or dense weeds, a solid blade is better because flexible line will wear out quickly and can also get tangled, stopping the motor. For simply trimming edges, they are both as good as each other.

Line trimmers

Often featuring a bent shaft, these are lighter in weight and usually less expensive than brush cutters.

The hub at the end of the shaft contains nylon lines that cut through grass and weeds as they are spun at high speed.

Line trimmers can be powered by petrol engines, mains electricity or batteries and are usually intended for lighter duty than brush cutters.

Brush cutters

The line trimmer’s beefier cousin, this tool normally features a straight shaft from the motor to a gearbox.

The torque is transmitted to a hub on which the blade spins parallel with the ground.

Brush cutters usually have a solid X or Y shaped blade instead of nylon cord as used on line trimmers. This packs a more powerful punch and lasts longer in heavy-duty applications.

Power options

A range of factors influence what power option will be best for you, including operating volume, portability and versatility.

Petrol

Powered by either a two-stroke or four-stroke motor, petrol line trimmers and brush cutters offer the widest range of options.

From dual-handle units that are used with a harness to split-shaft designs compatible with different accessories, petrol trimmers come with either a straight or bent shaft.

Ear protection must be worn during use as they are usually very noisy.

Electric

If you can get away with running an extension cord, then electric line trimmers can provide you with similar power to a petrol engine with lightweight and maintenance-free operation.

Light-duty units often have the motor mounted at the cutting end of the shaft, while more powerful trimmers have a motor mounted at operator height and feature a bent shaft.

Battery

With advances in technology, cordless line trimmers and brush cutters are rapidly growing in popularity.

Available with both bent and straight shafts, they offer the best of both worlds with quiet operation and cordless portability.

And with 36V models, there is no need to compromise on power, while heavy-duty 4.0Ah battery packs offer up to an hour of no-load running time.

Line trimmer attachment options

There are three main ways in which the cutting line is attached to the hub. The most common is bump feed, although automatic feed and manual options are also widely used.

Regardless of what type of line your trimmer uses, or even if you have a brush cutter with a solid blade, safety eyewear is always crucial as there is a very high risk of small debris being flicked at high speed towards the user.

Bump feed

The most common type, this holds about 3m of trimmer line wound onto an internal spool.

As the end wears down, the operator bumps the underside of the hub on the ground as it spins, releasing a regulated length of line.

The downside is that it can be quite time-consuming to wind on new line, but various manufacturers have developed ways to simplify the process.

Automatic feed

Fully automatic heads rely on the user re-spooling with exactly the correct size of trimmer line.

An internal counterbalance system works on the line weight to automatically release a measured amount of line as is needed.

This type of head is not normally found on petrol-driven units.

Manual feed

This type uses fixed lengths of reinforced, straightened line which are replaced as they wear down.

They usually last longer than the same amount of standard trimmer line, and are the quickest to replace.

Many line trimmers can be retrofitted with universal fixed-line units that can be mounted in place of a spool hub and feature three doubled lengths of fixed line.